Harvesting a Burl

Harvesting a Burl

Burls are abnormal tree growths that can occur on a tree’s stem (bole), on the roots or on a branch. Their cause is not completely understood; theories include a genetic tendency or a reaction to either a virus or a fungus. Possibly, all of these factors contribute to a varying degree. Some sources also attribute it to injury.

Bowl turned from a burl
Burl is sufficiently precious that it is often made into veneer. This copy of a 19th century writing desk made by the author is veneered with walnut burl. Such walnut burl veneer is refered to as “dashboard burl” because it was used on the dashboards of fine cars. Burl is also a popular choice for turned bowls.

Burls range in size from one that a turner would be hard-pressed to get a 6″ salad bowl out of to thousands of pounds, big leaf maple and redwood being examples of the latter. Today, these huge burls are often slabbed for live-edge furniture.

The comparative rarity and unusual appearance of these wood growths contribute to their appeal for woodturners (and other woodworkers) — but, before you can work with a burl, you have to find it and acquire it.

Finding Burls

Burl on a maple tree
This large maple burl at Ohio’s Geauga County Park is an example of the abnormal growth nearly surrounding the tree.

Many burls occur on the roots of a tree but go largely undetected for the simple fact that 60% of the biomass of any given tree is underground. If they occur at about the same rate on the roots as on the aboveground portion of the tree, the chances are 10% higher to have a root burl.

The lumbering industry does not harvest the roots of trees in either selective or clear cutting, leading to many burls going undetected. Nowadays, burl hunters dig up the roots of trees noted for having root burls, such as manzanita, rhododendron and laurel. All of these species are shrubs, making root harvesting easier. A certain number of root burls that are partially visible at the root knees get harvested as well.

Large burl on a cherry tree
This cherry tree growing in a stand of timber has a magnificent burl growing about three feet off the ground.

A watchful walk through any hardwood forest will invariably turn up a burl or two. In northeastern Ohio, cherry, maple, oak, buckeye (the Ohio state tree), ash, willow, locust and walnut burls are common.

Pulling a freshly cut tree with a skidder
After the Doll Lumber Company felled the tree, they used a skidder to drag the cherry log out of the woods.

Cherry burls are usually a prominent mound on the tree’s stem anywhere from ground level to just under the canopy. Burls of other wood species vary from a mound to almost surrounding the tree and can extend far up and down the stem as well. Sometimes the tree’s stem is completely covered with burls — a common condition of willows.

Burls are also common in yard trees, such that looking at roadside trees on any drive will turn up quite a number. Tree surgeons frequently encounter them, making these good people for turners to befriend.

Process of Harvesting

Cutting a burl off a cherry log with a chainsaw
Lumber company owner Jim Doll harvests a small burl from this cherry log by chainsawing it, cutting just under the bark above and below the burl.

Removing a small burl from a tree is straightforward: simply cut a little below where the burl is attached. Larger burls are not so easy. It is my feeling that harvesting burls is somewhat like cutting diamonds: there is a knack to it.

Burl after it has been cut from cherry log
The freshly harvested burl will now be painted with Sealtite 60, a wax solution that will prevent it from losing water rapidly.

As you can see on the huge oak burl in the photo, there are three visible lobes to this particular burl. A chainsaw cut down each of these fault lines would be the first order of business. Then the sections would be parted from the tree stem. They end up being like slices of an orange. Each section would be further sawn down to usable blanks or sent to a veneer mill.

Large harvested oak burl
During a 2017 open house for a regional American Association of Woodturners chapter, Jim Doll presented the huge oak burl shown here.

For 35 years, I have bought both kiln-dried wood and burl from Doll Lumber Company, a forestry and sawmill operation which is located about 10 minutes from my shop. In my online video for this article, Jim Doll shows his company’s process for harvesting burl.

Working With Burls

White ash bowl turned from a burl
This carved white ash burl bowl by the author was a core separation from a much larger bowl.

When it comes to working with wood from burls, there are a few things to keep in mind. Burl differs greatly from normal wood in that burl grain grows randomly in interlocking circles. This means that burl can be turned wet but does not change shape much from shrinkage during drying. Because the wood is essentially homogenized, it shrinks fairly equally in all directions.

Sharp tools always are a must, but you can cut in any direction, and scrapers work very well.

Because burl is expensive wood, many turners will make several nesting bowls out of one burl by making cone separations. A very large parting tool (or special curved cutters mounted in a fixture) is employed to cut into the bowl at approximately a 45° angle until only a small tenon is holding the cone, which can then be broken away by inserting a pry bar in the kerf and applying some force.

(I’ll discuss these processes by actually coring several bowls from the cherry burl harvested in this article in my next installment, and I’ll show how to complete the final turning of these cores in a subsequent article.)

Burl must be sanded well. Start with 80-grit and work to 180-grit in small steps.

I finish burl bowls with multiple coats of oil finish, waiting 24 hours between coats and sanding each new coat with finer paper. Second coat is 220-grit with the third and all subsequent coats at 320-grit.

Turning burls is great fun, and I encourage you to give it a try!

Workshop Organization

Today we look at the concept of de-cluttering and shop organization. I confess that, for the most part, I am better at accumulating clutter as opposed to organizing it. But that is kind of the point. Last night I looked for a hammer for about 10 minutes…I found it under the dog bed.

So whether we are talking clamp racks, or stackable storage totes to advanced systems, I am really interested in them. So check out our videos for some great organizational information.

Rob Johnstone, Woodworker’s Journal

P.S. The video contains details about our next giveaway. Tune in to find out more!

Featured Videos

Organize Cabinet Drawers with the Lock-Align System

Organize any drawer — and keep it that way — with the Rockler Drawer Organizer System. Use the interlocking trays, bins and dividers to build a tidy grid of compartments that is customized not only to the size of your drawer, but also to the tools and hardware that you need to sort. The trays interlock side-to-side and line up end-to-end to fill out drawers of any width or depth. When you get to the final piece at the end of the row, simply cut it to fit with an ordinary pair of scissors. The synthetic rubber material is easy-to-cut, and the grid of cutlines on the back side ensures that the interlocking feature still works once the tray is cut.

Router Table Organizer Cabinet

Check out all the cool custom features that are part of this Router Table Organizer Cabinet project. Many router tables feature an open base that is unused space. Chris Marshall built custom storage cabinets and shelves to fill the empty space under his Rockler router table.

More Video Feedback

More Video Feedback

We got quite a bit more Feedback in our inbox this week about the changes to the Weekly format. Keep it coming. We’d love to hear what you think – good or bad. – Editor

“I like the new format. Your videos have always been excellent and very informative. Keep up the good work.” – Keith Wales, Sr.

“I have really enjoyed your information over the years. I am certainly happy to get your eZine. I always read through it pretty much right away, selecting the things that pique my interest, and sometimes looking at the other things later. Since I am still a triceratops myself, I would rather read than have to wait for the video to go all they way through to the end. Frankly, I am able to read faster than the time it takes for me to listen to the video. And, I can be selective when I read just the items of interest to me. With the video, I have to watch it all they way through, or at least I think I have to do that. Anyway, the video, while great for some folks, it is NEVER an all or nothing thing in life. (Yeah, I was told to never use the word “never”, unless I mean it…and I do in this case). I am fine with the video, but please continue to also give me the option of reading what I want without having to listen to the whole darn video.” – Dave Dietz

“I don’t like the new format. Please go back to the old one. We have all the videos we need on YouTube.” – John Dack

Finishing Options for Garden Beds?

Finishing Options for Garden Beds?

In addition to woodworking, I am also an organic gardener. I am building a raised bed for asparagus, a bed I hope to exist for 20-plus years. I have chosen 8/4 x 10″ (about 100′) rough cedar to box the bed. I was about to use tung oil to finish all surfaces when I got August 2018’s issue in which the “Shou Sugi Ban Side Table” was featured, as well as your finishing article “Finishing Outdoor Furniture“. The burning seemed like a cheap solution until I read to use tung oil plus burning. Your article seemed to advocate tung oil, but thought it needed reapplying every couple of years. And then I saw that tung oil is about $60/gallon, and I might need two gallons. One edge and side will be exposed to soil and its critters. The other edge and side will be exposed to air and weather. Burn it? Tung it? Spar varnish? Maybe a good deck stain? What to do?

– Marvin Wachs
Joplin, Missouri

Raised garden segment made from redwood
While our reader planned to build a raised garden bed out of cedar, the one shown here — freshly built, unfinished and unweathered — is redwood.

One of the great myths of outdoor woodworking is that the “right” finish will add the properties you really want the wood to have. It won’t. Thus, I would have started by choosing a wood with high natural resistance to rot and bugs. Old-growth red cedar fits that category, but the cedar we buy today does not. Whatever you do in terms of finish will not change the essential nature of the wood and will provide only very short-term protection, if that.

I haven’t seen any lab tests confirming it, but I’d suspect that of all the finishes you listed — and all of them are certainly acceptable exterior finishes — I’d guess that burning, either with or without oil, will offer the most protection, as it creates a layer of carbon atop the wood.

Personally, I’d line the inside of the planter with an inert gardening plastic, something made to be in constant contact with water and soil. If you use a plastic liner to isolate the soil from the wood, there’s no reason you can’t substitute pressure-treated wood (yes, there is pressure-treated cedar) for more longevity. And, yes, I see the irony in pressure treating new-growth cedar to make it behave the way old-growth cedar does naturally.

Simple Woodworking Finishes

In last week’s Weekly, we offered a chance to win a $100 Rockler gift card and I’m happy to say that we found a winner! Congratulations, and I hope you find something cool to buy! Speaking of things that are cool, I hope you all are keeping cool during this heat wave! I know our shop has been doubling as the office sauna lately.

Also in this issue, I’m going to share my tips for finishing open and close grained hardwoods. Those videos are part of a series of six simple finishes recipes that I’ve done for Rockler. I think they’re pretty neat. Check them out and let me know what you think.

Rob Johnstone, Woodworker’s Journal

Featured Videos

Stain Finish for Open Grained Hardwood

Examples: Oak, Ash, Mahogany, etc.

How to apply this finish:

1. Sand the project up through the grits until at least 220-grit. It is a good idea to sand pieces that will be hard to reach before assembly.
2. Wipe the project with mineral spirits to check for glue splotches
3. Apply a good quality Oil Pigment Stain, dry 24 hours (Oil stains are easier to apply)
4. Use a good quality urethane top coat finish. Flood it on, let it sit and wipe it off. Let towels dry flat and dispose of properly!
5. If you have any nail holes, cracks or defects in the wood, fill them now with a wood filler putty that matches the color of the stained wood (sand smooth).
6. Apply at least two more coats urethane top coat finish.
7. Optional: After the finish has cured for 72 hours, apply a coat of high-quality paste wax and then polish it off.

Stain Finish for Close Grained Hardwood

Examples: Maple, Birch, Beech etc.

How to apply this finish:

1. Sand the project up through the grits until at least 320-grit
a. It is a good idea to sand pieces that will be hard to reach before assembly.
2. Wipe the project with mineral spirits to check for glue splotches
3. Apply a good quality Gel Stain, let dry 24 hours
4. Use a wipe-on polyurethane-type finish
a. Flood it on and wipe it off
b. Let rags dry flat and dispose of properly!
5. If you have any nail holes, cracks or defects in the wood, fill them now with a wood filler putty that matches the color of the stained wood (sand smooth)
6. Apply at least two more coats of the urethane
7. Optional: After the finish has cured for 72 hours, apply a coat of high-quality paste wax and then polish it off.
8. Optional: Substitute a wipe-on Danish Oil applied in the same manner.

More Video: Yea or Nay?

More Video: Yea or Nay?

Last week we launched a new iteration of the Weekly that will include more video content in each issue. Rob asked for your feedback about the format change, and a number of you have responded in kind. – Editor

What a difference! Love the videos. I’m going right out and buying myself a lathe, now that I know what’s best for me. – Richard Adams

Reading is faster and less disruptive. It’s also easier to skim through. All in all, I’m not a fan of video only. – Tom Fink

The Weekly as a video is great. As a legally blind person, it saves me the frustration of turning on the zoom (300%) or using a narrator (mine doesn’t work with eZine text). Plus everything makes better sense with video. I just hope all these videos will be archived for the readers, as I really haven’t found a program to save videos to the computer. Thanks again. This is very much appreciated. – Carl Timko

Thanks for the great job you do on the magazine and the Weekly. The videos were good this week. To be honest though, I enjoy the previous format. I often read my emails on my smartphone and would read the Weekly info from you. The videos don’t work as well on my phone and are harder to see. Whereas before I could enjoy the Weekly content wherever I was when I received it, now I will need to take time to sit down at my computer in order to watch the videos. Since I don’t sit down at the computer that much, and when I do, it is to get specific tasks done, this new format is not going to be as convenient as it was previously. I know I may be in the minority in this regard, but since you asked for feedback, I thought I would reply. Thanks again for the great job you do. – Mike Grawvunder

Great idea. I’ll look forward to it each week. – Bruce Mitchell

I am going to have to vote against the new video format. Those of us who prefer to live in the middle of nowhere (the Texas Hill Country in my case) can only get high speed internet by satellite. That means we have limited data allowances on metered connections. It doesn’t take many videos to eat up my 10 GB per month. Since I supplement my Social Security and state pension by taking on-line surveys, I need to be especially careful about streaming or downloading video. – Jim White

A video about choosing woods for outdoor projects in last week’s issue prompted one reader to share a species that other readers might not have tried for interior projects. – Editor

I appreciate Chris Marshall’s informative video on wood species for outdoor applications. One wood that is common and inexpensive at mills here in western Virginia, but I have never seen recommended for outdoor use, is black locust. It is very hard and very heavy, but kiln-dried black locust furniture will still be used by my grandchildren. The biggest limitation I have found (other than that it dulls my tools pretty fast) is that it is rarely available in widths over 4 or 5 inches. – Andy Mahler

CNC Routing: Five Fast Facts

CNC Routing: Five Fast Facts

Why would anyone confuse programming a computer with woodworking? One reason is that a CNC (computer numerically controlled) router can do some things that you just don’t want to do. In the same way that you could plane a huge board of rough stock smooth with a hand plane, but instead choose to use a jointer and planer, a CNC router can take the drudgery away, leaving you with the fun stuff.

1. Carving the easy way. From time to time, a carved panel just might look wonderful in a piece of casework: a pair of doors, perhaps with matching motifs; a backsplash that has a geometric pattern repeating across its length; a carved architectural component. If carving is outside your wheelhouse of woodworking skills, a CNC router can come to your rescue. Those carved accents can enhance your project, and you get the credit!

Routing patterns with a bit in a CNC machine

2. Drilling is boring. Let’s say you have a couple hundred holes to drill for a cribbage board. It’s a doable job with a drill/driver or a drill press, but an arduous one. Now imagine making five cribbage boards for holiday gifts: you’ll have 1,000 holes to drill! If done by hand, just imagine how tedious the task would be! Not for a CNC. It will drill holes all day long without complaint.

3. CNC simplifies complex interfaces between workpieces. For example, Woodworker’s Journal once presented a Longworth Chuck project for woodturning with many curved slots that need to perfectly relate to one another. Unless they align precisely, the chuck won’t open and close smoothly. A CNC’s precision enables it to machine slots like these accurately, upping your odds for success the first time while also reducing your stress.

Table with an inlay routed by a CNC machine

4. “May I have five more?” Have you ever agreed to build a bunch of things for your child’s school or for a church function? After you have completed the 20th little widget and you are staring down another 100 to go, you think to yourself: “There has got to be a more efficient way…” It’s CNC. Set the machine to work in the background to free yourself for more enjoyable shop tasks.

5. Consider it a sign! Of course, one of the best uses of CNC technology in the home shop is for sign-making. It can machine awards, cabin signs, humorous gifts, address plaques and much more. Most home shop CNCs come with sign-making programming already preloaded, along with fancy fonts and scripts with the lettering properly spaced. Here’s a moneymaking opportunity!